There is an urgent need for high-quality rainfall observations with high spatial and temporal resolutions in catchment hydrology, particularly in urban hydrology. Weather radars are in principle well-suited for that purpose, but often need adjustment. Usually, only a few raingauge measurements are available as input for hydrological models or to adjust the radar data in real-time. X-band radar data, specifically interesting for urban hydrology, are often not available. Previous studies have shown that (commercial) microwave link data are suitable to calculate path-averaged rainfall intensities and, therefore, are a potentially valuable source of additional rainfall information. This is further explored in this study using data from 321 links from a commercial cellular telephone network in the Netherlands. Some preliminary results are presented concerning the derivation of rainfall maps and the correction of radar data using microwave link data.